Process-induced damage is becoming a very serious concern for semiconductor device manufacturer's. Such damage accounts for device degradations and lower yields. One type of process-induced damage is charge-induced damage. Charge-induced damage can occur during plasma etch and plasma-enhanced deposition processes (collectively referred to as plasma charging damage), ash, and ion implantation. Charge-induced damage is becoming particularly important due to: the scaling down of gate oxide thicknesses and channel length with succeeding technologies; increasing levels of metallization; and the advent of high density plasma sources for etching and deposition.
Charge collection in processes that use photoresist (more specifically, nonconductive photoresist) masking, such as etch processes, may occur along the edge of the antenna pattern or other conductor. However, in processes that do not involve resist (like implantation and deposition), the charge collection may occur over the area of the antenna (or other conductor). Thus, ascertaining whether a charging phenomena is area or perimeter (edge) related would more effectively enable the pinpointing of the process step the charging phenomena occurred in.
In charge-induced damage, the charge collected in the antenna stresses the oxide of a device. More specifically, in a MOSFET structure, the charge collected on the antenna stresses the gate oxide of the MOSFET, thereby inducing stress-related degradation of the MOSFET. This stress-related degradation may include: shortening the lifetime of the device, increasing the gate leakage of the device, or shifting the threshold voltage of the device.